feat(server): hot-reload config store and reloadable infra clients

- Replace single Load() with a watching Store that re-reads config files
  (and config.local.yaml) and fans out a ReloadEvent with a per-field diff
  so consumers can decide whether the change is hot-applicable or requires
  a process restart.
- Wrap llm, retrieval, vector store, and object storage clients in
  Reloadable* shells so the bootstrap can swap their underlying impls when
  config changes without re-instantiating handlers.
- Make jwt.Manager and ops TokenIssuer mutable under a lock so secrets and
  TTLs can be rotated live; thread default plan code through a setter on
  the ops AdminUserService.
- Wire ConfigStore through bootstrap and every cmd/main.go, scheduler /
  worker / tenant-api / ops-api start the watcher; services and handlers
  take a config.Provider so they always read current values for things
  like generation.stream_enabled, scheduler dispatch, retrieval, etc.
- Switch shared/config decoding off viper to a Kratos-derived runtime
  package so env placeholders (\${VAR:default}) resolve consistently and
  the same source machinery powers both the loader and the watcher.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/shared/auth/jwt.go

@@ -3,6 +3,7 @@ package auth
 import (
 	"crypto/sha256"
 	"fmt"
+	"sync"
 	"time"
 
 	"github.com/golang-jwt/jwt/v5"
@@ -10,17 +11,27 @@ import (
 )
 
 type Manager struct {
+	mu         sync.RWMutex
 	secret     []byte
 	accessTTL  time.Duration
 	refreshTTL time.Duration
 }
 
 func NewManager(secret string, accessTTL, refreshTTL time.Duration) *Manager {
-	return &Manager{
-		secret:     []byte(secret),
-		accessTTL:  accessTTL,
-		refreshTTL: refreshTTL,
+	m := &Manager{}
+	m.Update(secret, accessTTL, refreshTTL)
+	return m
+}
+
+func (m *Manager) Update(secret string, accessTTL, refreshTTL time.Duration) {
+	if m == nil {
+		return
 	}
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.secret = []byte(secret)
+	m.accessTTL = accessTTL
+	m.refreshTTL = refreshTTL
 }
 
 type TokenPair struct {
@@ -32,6 +43,7 @@ type TokenPair struct {
 }
 
 func (m *Manager) Issue(userID, tenantID, primaryWorkspaceID int64, role string) (*TokenPair, error) {
+	secret, accessTTL, refreshTTL := m.snapshot()
 	now := time.Now()
 	accessJTI := uuid.New().String()
 	refreshJTI := uuid.New().String()
@@ -45,10 +57,10 @@ func (m *Manager) Issue(userID, tenantID, primaryWorkspaceID int64, role string)
 			ID:        accessJTI,
 			Subject:   "access",
 			IssuedAt:  jwt.NewNumericDate(now),
-			ExpiresAt: jwt.NewNumericDate(now.Add(m.accessTTL)),
+			ExpiresAt: jwt.NewNumericDate(now.Add(accessTTL)),
 		},
 	}
-	accessToken, err := jwt.NewWithClaims(jwt.SigningMethodHS256, accessClaims).SignedString(m.secret)
+	accessToken, err := jwt.NewWithClaims(jwt.SigningMethodHS256, accessClaims).SignedString(secret)
 	if err != nil {
 		return nil, fmt.Errorf("sign access token: %w", err)
 	}
@@ -62,10 +74,10 @@ func (m *Manager) Issue(userID, tenantID, primaryWorkspaceID int64, role string)
 			ID:        refreshJTI,
 			Subject:   "refresh",
 			IssuedAt:  jwt.NewNumericDate(now),
-			ExpiresAt: jwt.NewNumericDate(now.Add(m.refreshTTL)),
+			ExpiresAt: jwt.NewNumericDate(now.Add(refreshTTL)),
 		},
 	}
-	refreshToken, err := jwt.NewWithClaims(jwt.SigningMethodHS256, refreshClaims).SignedString(m.secret)
+	refreshToken, err := jwt.NewWithClaims(jwt.SigningMethodHS256, refreshClaims).SignedString(secret)
 	if err != nil {
 		return nil, fmt.Errorf("sign refresh token: %w", err)
 	}
@@ -75,16 +87,17 @@ func (m *Manager) Issue(userID, tenantID, primaryWorkspaceID int64, role string)
 		RefreshToken: refreshToken,
 		AccessJTI:    accessJTI,
 		RefreshJTI:   refreshJTI,
-		ExpiresAt:    now.Add(m.accessTTL).Unix(),
+		ExpiresAt:    now.Add(accessTTL).Unix(),
 	}, nil
 }
 
 func (m *Manager) Parse(tokenStr string) (*Claims, error) {
+	secret, _, _ := m.snapshot()
 	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(t *jwt.Token) (interface{}, error) {
 		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
 			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
 		}
-		return m.secret, nil
+		return secret, nil
 	})
 	if err != nil {
 		return nil, err
@@ -96,8 +109,25 @@ func (m *Manager) Parse(tokenStr string) (*Claims, error) {
 	return claims, nil
 }
 
-func (m *Manager) AccessTTL() time.Duration  { return m.accessTTL }
-func (m *Manager) RefreshTTL() time.Duration { return m.refreshTTL }
+func (m *Manager) AccessTTL() time.Duration {
+	_, ttl, _ := m.snapshot()
+	return ttl
+}
+
+func (m *Manager) RefreshTTL() time.Duration {
+	_, _, ttl := m.snapshot()
+	return ttl
+}
+
+func (m *Manager) snapshot() ([]byte, time.Duration, time.Duration) {
+	if m == nil {
+		return nil, 0, 0
+	}
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	secret := append([]byte(nil), m.secret...)
+	return secret, m.accessTTL, m.refreshTTL
+}
 
 func HashToken(raw string) string {
 	h := sha256.Sum256([]byte(raw))